The first phase of the Institute’s activities included five projects: Constructing the Syntax of the Serbo-Croatian Language (Lj. Jonke), The English Element in Serbo-Croatian and in European Languages, Phase 1 (R. Filipović), Personal Onomastic of the Roman Illyric (R. Katičić), Researching the Istro-Romanian Dialect (A. Kovačec), Investigating Greek and Dalmatic Remains of Adriatic Islands (V. Vinja).

In the second phase of the Institute’s activities, the following projects stand out: an international project, Serbo-Croatian – English Contrastive Project, a cooperation of domestic researchers and linguists from the Centre for Applied Linguistics, Washington, started in 1967 (R. Filipović). A Five-language Contrastive Project: German - S. Žepić, Russian - A. Menac, Italian - J. Jernej, French - Ž. Klaić, and Spanish - K. Budor. In the meantime, the Zagreb Croatian - English Contrastive project was also initiated (R. Filipović), along with a smaller project entitled Contributions to the Description of Hindi (M. Jauk Pinhak).

Apart from long-term research within the contrastive projects, several others were conducted from 1971 to 1975: The History of 19th Century Croatian Literary Language (Z. Vince), Researching Romance Languages and Their Elements in the Territory of SR Croatia and SFR Yugoslavia (V. Vinja) – this project was divided into four subtopics: Etymological Dictionary of the Adriatic Fauna (V. Vinja), Establishing and Harmonising Italian Terminology from the Field of Social Life on our State Territory (J. Jernej), Sephardi Speech of Bosnia, Croatia, Macedonia and Serbia (A. Kovačec), and Aromanian Speech of SFR Yugoslavia (A. Kovačec). In this period, the following new projects were introduced: Researching the Phraseology in Russian and Croatian Literary languages (A. Menac), Computational Analysis of the Texts of Old Croatian Literature (Ž. Bujas and M. Moguš), English - Croatian Lexicographic Corpus (Ž. Bujas), Croatian Toponyms in English Travel Literature and The English Element in European Languages (R. Filipović).

From 1976 to 1980, changes were introduced in the structure of research projects, organising all of them within two major, more extensive scientific projects: The Study of Croatian Literary Language and The Contrastive Study of Croatian or Serbian Language in Relation to Foreign Languages. Within those two projects, several smaller ones were conducted, some of which were continuations or expansions of earlier individual projects or entirely new ones: Computational Analysis of the Texts of Older Literature, Study of 19th Century Croatian language, Corpus of Texts of Contemporary Croatian Literary Language (M. Moguš), Dictionary of Econyms, their Ethnics and Kthetics (S. Babić). As part of the project Croatian Phraseological Problematic, led by A. Menac, a series of small Phraseological Dictionaries was initiated. V. Vinja was head of the Etymological Dictionary of Dalmatic Elements in Croatian. Within existing projects, new assignments were set: the Making of a Dictionary of Croatian Library Science (A. Horvat), Characteristics of text construction as language and information unit (Z. Glovacki-Bernardi) and The Lexicon of the Town of Korčula (D. Kalogjera).

While in the period from 1980 to 1990, work on said assignments continued, some new projects were started. In 1989, the Institute joined the international project Language Industries, organized by the Council for cultural cooperation of the Council of Europe, Strasbourg. Work on contrastive analysis continued throughout this period with the contrastive analysis of English and Croatian (R. Filipović), French and Croatian (Ž. Klaić), German and Croatian (S. Žepić), Russian and Croatian (A. Menac), Spanish and Croatian (A. Kovačec) and Italian and Croatian (Z. Vučetić). Since 1986, contrastive analyses of Greek, Latin, Modern Greek and Croatian under the leadership of O. Perić, while somewhat later the contrastive analysis of Macedonian and Croatian was introduced, led by B. Pavlovski. Also continued was the work on the following projects: Problems of Lexicological-semantic Correspondences in Hindi and Croatian (M. Jauk-Pinhak) and Procedures in the Translation of Elements of Culture and Civilization (V. Ivir).

Since 1991, the Institute has conducted eight different projects, some of which were continuations of earlier research, while others represented entirely new research: Principles of the Organization of Vocabulary (M. Žic Fuchs), French Descriptive Grammar with Special Regard to Croatian Grammar (M. Kačić) and Dialects and Standards of the English Language (D. Maček). In 1996, the Ministry of Science and Technology approved the funding for the following five projects: Semantic Fields and Syntax (M. Žic Fuchs), Comparative Grammars: Croatian and French (M. Kačić), Croatian-German Language Relations (Z. Glovacki-Bernardi), Researching West Slavic Languages (D. Sesar) and Computational Analysis of the Croatian Language (V. Muhvić-Dimanovski).

Work on the project Computational Analysis of the Croatian Language continued in the period from 2002 to 2006, focusing primarily on the construction of the one million-entry corpus of Croatian (led by M. Tadić). A new project, Neologisms – problems of theory and application (V. Muhvić-Dimanovski), was initiated in this period. From 2007 in the Institute a research programme with several projects was conducted: Computational-linguistic models and language technologies for Croatian and Croatian language resources and their marking (M. Tadić), Computational syntax of Croatian (Z. Dovedan), Lexical semantics in building Croatian WordNet (I. Raffaelli), Informational technology in translating and e-learning of Croatian (S. Seljan), Discovering the knowledge in text (B. Dalbelo). The work on corpus of neologisms continued under the project Neologisms in Croatian and European Context (V. Muhvić-Dimanovski).

The Institute was also one of the active partners in several international projects: ACCURAT (Analysis and Evaluation of Comparable Corpora for Under Resourced Areas of Machine Translation, FP7), with M. Tadić as head of the Croatian research team, LetsMT! (Platform for Online Sharing of Training Data and Building User Tailored Machine Translation, ICT PSP), also headed by M. Tadić. From 2006 to 2010, two members of the Institute worked in collaboration with the Institute for Anthropological Research (as one of nine European partners) on the project LINEE (Languages in a Network of European Excellence), within the program FP6.

In 2010 and 2011, the Croatian Ministry of Science, Education and Sports financed a two-year bilateral project with Slovenia entitled Interlingual and Intercultural Relations and the Construction of National Identity in Slovene and Croatian Tourist Discourse, headed by V. Muhvić-Dimanovski and V. Mikolič from the University of Primorska, Koper. During 2015 and 2016 University of Zagreb financially supported the project Linguistic identities of Croatian migrant community in Argentina (led by A. Skelin Horvat) and the project HR4EU: Portal for Online learning of Croatian (led by M. Tadić) and financed by European Social Fund. From its very beginnings, the Institute has focused not only on scientific research but also on the application of the accomplished results in graduate and post-graduate courses.